Common methods of applying permanent or semi-permanent color to tissue include tattooing and application of inks. Corneal tattooing has been used to provide Cosmesis for iris defects and to create a pupil in aniridia. These techniques involve the implantation of tattoo pigments into the corneal lamellae. In skin tattoos, pigments are injected just below the epidermis and just above the papillary dermis using special needles. Inks, particularly India inks, are traditionally used to mark tissues prior to surgical procedures. Alternative methods to mark tissue surfaces use alcian blue, artist's pigments, and typist's correction fluid. None of these marking modalities are used for therapeutic benefit.
Many chemical dyes are in the form of sulfonic acids. Sulfonic acids, anhydrides, sulfonyl chlorides, and acid chlorides are classes of chemical compounds that react with free amines of proteins resulting in the covalent attachment of the specific chemical moieties to proteins. These compounds are commonly known as acylation reagents. Acylation of amino groups in proteins has been widely used (“Chemical Reagents for Protein Modification”, 2nd. Edition, Ed. Roger L. Lundblad, CRC Press, Boca Raton, 1991). Such reactions have been used to introduce structural probes into proteins at specific sites to modify lysyl residues. Acylation reactions have been used to derivatize soluble and insoluble collagen and have been described by DeVore, et.al. in series of patents (U.S. Pat. Nos. 4,713,446, 4,851,513, 4,969,912, 5,067,961, 5,104,957, 5,201,764, 5,219,895, 5,332,809, 5,354,336, 5,476,515, 5,480,427, 5,631,243, and 6,161,544). However, none of these patents describe the use of acylation to stain or dye surfaces or sections of intact tissue.
The present invention describes methods for localized and controlled staining of intact tissue surfaces to provide therapeutic benefit in ophthalmic applications.